update text file editor model when file associations change

src/vs/workbench/common/editor/textEditorModel.ts

@@ -153,6 +153,20 @@ export abstract class BaseTextEditorModel extends EditorModel implements ITextEd
 		this.textEditorModel.setValueFromRawText(rawText);
 	}
 
+	/**
+	 * Updates the text editor model mode based on the settings and configuration.
+	 */
+	protected updateTextEditorModelMode(mime?: string): void {
+		if (!this.textEditorModel) {
+			return;
+		}
+
+		const firstLineText = this.getFirstLineText(this.textEditorModel.getValue());
+		const mode = this.getOrCreateMode(this.modeService, mime, firstLineText);
+
+		this.textEditorModel.setMode(mode);
+	}
+
 	/**
 	 * Returns the textual value of this editor model or null if it has not yet been created.
 	 */